Without wearing a safety helmet, a motorcyclist is rather vulnerable to head injury when an accident takes place. The safety-conscious bicyclists are also becoming aware of the importance of wearing a safety helmet. Generally speaking, a safety helmet is composed of a shell of a plastic material. The inner side of the shell of the safety helmet is furnished with a shock-absorbing layer Fastened thereto for providing a wearing comfort and protecting the head from an impact.
The conventional methods of making a safety helmet are summed up hereinafter.
The conventional safety helmet is generally composed of a shell of a plastic material. The shell is provided on the inner side thereof with a layer of an expanded polystyrene material. The expanded polystyrene layer is provided with a soft layer of a cotton material for preventing the head from making contact with the expanded polystyrene layer. The method of making such a conventional safety helmet as described above is not cost-effective.
Another conventional safety helmet is composed of a shell of a plastic material. The shell is provided on the inner side thereof with a layer of a foam material. The foam material layer is formed integrally with the shell in a molding tool at a predetermined temperature and under a predetermined pressure. The foam material layer is intended to provide the shell of the helmet with a cushioning effect. However, in the process of making the helmet, the foam material layer is not attached securely to the surface of the upper mold cavity of the molding tool, thereby causing the foam material layer to have a rough surface which can cause a wearing discomfort and is therefore covered with a soft layer of a cotton material at an additional cost. The method of making this type of the safety helmet is also inefficient.